1. Field of the Invention
The present invention relates to the field of video systems.
2. Prior Art
Work has been done on various types of video systems whereby a viewer may interact with the video programming being presented. While a system could readily collect data provided by the viewer during programming such as, by way of example, yes, no or multiple choice answers to questions presented during the viewing, which answers could readily be correlated with the time of the responses during the programming for scoring and/or other evaluation, the ultimate goal in such systems is to have the further programming itself respond to or be dependent upon a prior viewer response or responses so that the viewer truly interacts with what he is being shown to determine what will subsequently be viewed. By way of example, in the case of educational materials, a problem might be presented by way of a video picture and supporting audio, with the viewer's solution to the problem resulting in a notation that the answer was correct, followed by the presentation of the next problem or, in the alternative, an indication that the answer was wrong and an explanation of why the answer was wrong. Depending upon the number of paths or tracks which are possible, the degree of difficulty of the following problem may be based upon the accuracy of the preceding answers, so that better students will not be bored by a lack of challenge, and lesser students will not be frustrated by the lack of results. In the case of entertainment, a truly interactive system will allow viewer's responses to affect one or more succeeding storyline segments to the viewer's amusement, with or without scoring as the case may be.
In video disc systems, the video and audio signals are stored on circular tracks on the video disc, two fields or one full frame per track. For ordinary programming the pickup head is advanced to the next track during the vertical retrace so that there is no interruption of the material being viewed. Since the pickup head potentially may be moved anywhere, various types of interactive video systems based on video disc technology have been proposed. However, the extent of head motion without momentary loss of signal is limited, though improvements are being made in that regard, and a momentary loss of picture in educational systems may be acceptable. In general for each jump, the fields for the sequence jumped to are presented sequentially, together with the audio information therefor, so that no problem is encountered in providing the audio associated with that video sequence. However, interactive video disc systems by their nature depend on the ability to determine the audio and video signals by physical selection of the tracks on the video discs, and thus by controlling the video signal itself. Consequently, this technology is not transferable to over the air programming and is not applicable to sequential recording and playback systems, particularly video cassette recorders currently in use in large numbers.
Finally, any video sequence may be altered at any point by overlaying or substituting computer graphics therefor. However, while this is useful for special effects and short term changes, very definite limitations are encountered in terms of resolution, real time animation and the amount of data which can be accumulated in the computer for the display.
The assignee of the present invention has developed methods and systems which allow the interleaving of fields from multiple story lines, with a field of a selected story line being stored in a refresh memory until the next field of that story line is presented in the video signal. Certain signal segments may consist of a single story line, which then may branch to multiple lines, with those in turn branching to additional multiple lines, etc., or converging to lesser numbers of story lines as desired. Consequently, on viewing, the viewer will view a complete story line made up of story line segments determined by the viewer's response at various times throughout the program, which responses determine which of the multiple story line segments are concatenated to form the resultant overall story line. In such a system one could use the left and right stereo channels as two independent audio channels, though in general one would like to be able to select between more than two channels at various times. Also, such an arrangement would not provide any ability to imbed digital data of various forms in the signal such as might be useful for graphics commands, branch point identifications, number of story lines to be selected from, etc. Also, while a signal comprising multiple interleaved story lines would not be compatible with an ordinary TV receiver, it is desirable to have the capability of multiple audio story lines and digital data of various forms imbedded in the TV signal in such a way as to not interfere with the reception of the main story line on an ordinary receiver, whereby a TV broadcast signal compatible with ordinary receivers and broadcast techniques may provide at least some of the interactive capabilities when received on the special equipment also usable for a full interleaved interactive video system.
Thus, a main object of the present invention is to provide a means for imbedding digital data and multiple audio (analog) track information in a video signal in a manner compatible with ordinary broadcast TV and transparent to a conventional television receiver, but which may provide multiple independent audio tracks and a substantial level of interaction with a viewer utilizing special reception equipment, which equipment may be utilized to provide a fully interactive system from signal sources not required to be compatible with conventional receivers. This and other objects of the invention will become apparent from the description to follow.